In the drilling, production, transport, storage, and processing of crude oil, including waste water associated with crude oil production, and in the storage of residual fuel oil, hydrogen sulfide and mercaptans are often encountered. The presence of hydrogen sulfide and mercaptans is objectionable because they often react with other hydrocarbons or fuel system components. Further, hydrogen sulfide and mercaptans are often highly corrosive as well as emit highly noxious odors. Uncontrolled emissions of hydrogen sulfide gives rise to severe health hazards. Burning of such vapors neither solves toxic gas problems nor is economical since light hydrocarbons have significant value.
Furthermore, hydrogen sulfide and mercaptans are often present in the underground water removed with the crude oil, in the crude oil itself and in the gases associated with such water and oil. When the water and oil are separated from each other, hydrogen sulfide is emitted as a gas which is associated with water and hydrocarbon vapors. Natural gases further often contain hydrogen sulfides.
The use of various compounds to react with hydrogen sulfide and mercaptans has been known in the art. For example, U.S. Pat. No. 6,063,346 discloses the use of a combination of triazines, maleimides, formaldehydes, amines, carboxamides, alkylcarboxyl-azo compounds and cumine-peroxide compounds for the removal of hydrogen sulfide and mercaptan contaminants from a fluid. U.S. Pat. No. 5,128,049 further discloses the use of certain triazine, morpholino and amino derivatives for the removal of hydrogen sulfide content from fluids.
Generally, such compounds are either too expensive for commercial use or evidence insufficient levels of mercaptan and/or hydrogen sulfide removal. Better alternatives for the removal of hydrogen sulfide as well as mercaptans have therefore been sought.